Russia, Turkey and Iran agreed in a memorandum signed on May 4 to establish four separate de-escalation zones in Syria for at least six months, according to a text detailing the agreement published by the Russian foreign ministry on Saturday.The largest de-escalation zone includes Idlib province and adjoining districts of Hama, Aleppo and Latakia provinces. The other three zones are in northern Homs province, the Eastern Ghouta region east of the capital Damascus and along the Jordanian border in southern Syria.The guarantors will finalize maps of the de-escalation zones by June 4, and the agreement can be extended automatically if the three guarantor states agree.The agreement envisages the halt of hostilities between Syrian government forces and armed opposition groups within the zones and the creation of conditions for humanitarian access, medical assistance, the return of displaced civilians to their homes and the restoration of damaged infrastructure.The guarantor states committed to take all the necessary measures to continue fighting Islamic State, Nusra and other groups both within and beyond the de-escalation zones.Political and armed opposition groups in Syria have rejected the proposal, saying Russia has been unwilling or unable to get PresidentBashar al-Assad and his Iranian-backed militia allies to respect past ceasefires.(Reporting by Maria Kiselyova and Lisa Barrington; Editing by Keith Weir) --- ---...